Should we consider a BOV

[CoolAirVw]

My VDO gauge makes a buzz (fart) as it exhaustes the boost pressure when everything is clean.

Maybe it ate too much saurkraut? :lol:  :shock:  :shock:  :lol:  :roll:

[saurkraut]

My VDO gauge makes a buzz (fart) as it exhaustes the boost pressure when everything is clean.

Maybe it ate too much saurkraut? :lol:  :shock:  :shock:  :lol:  :roll:

That applies primaily to the driver.  :wink:

Maybe a blow off valve is a good idea after all.   :oops:

[myke_w]

My personal experience with a BOV on a TD is not a good one.

On my TD Vanagon I was running with the wastegate adjusted for boost above the BOV threshold (about 9-10 lb IIRC). Under normal around town circumstances it wasn't a problem, but when climbing a hill and really running it hard, the boost would overcome the BOV and I could hear pressurized air exiting the manifold through the BOV (the loud whoosh all you kids are after ).
It would do this in bursts if you held the pedal down. EGT's skyrocketed.

In a gasoline engine this is no big deal, a rich mixture never blew anybody's gasser up, diesel on the other hand  :roll:

I theorize that as the pressure was being released, copious amounts of fuel were still be injected, the turbo was still making boost & demanding fuel from the injection pump, but the air wasn't present in the combustion chamber because it was bleeding off, which severely richened the mixture.

After that trial, I nixed the BOV and relied singly on the wastegate to regulate boost pressure. I based my settings on maximum attainable EGT of 1300 on a WOT lug run to the top of this huge hill by my house.

All one really needs for safe functionality is a boost controller valve, a boost guage and a wastegate.

[Turbinepowered]

My VDO gauge makes a buzz (fart) as it exhaustes the boost pressure when everything is clean.

Maybe it ate too much saurkraut? :lol:  :shock:  :shock:  :lol:  :roll:

That applies primaily to the driver.  :wink:

Maybe a blow off valve is a good idea after all.   :oops:

Natural gas enrichment under full load?

[smutts]

many many "boost gauge install kits" have a tee with a restriction build in... the restriction damps the small pulses in boost around 0 that cause the needle to buzz against the zero stop.

And there was I stuffing some cigarette end in the gauge tube.

[CoolAirVw]

All one really needs for safe functionality is a boost controller valve, a boost guage and a wastegate.

And a............  pyrometer.  

Or am I just wanting more gauges,  to pimp my ride, cuz its cool?

[vanagonturbo]

No. A pyro is #1 gauge in my book. Butt dyno will tell you if you are getting too much or too little boost.

FWIW, my interest in the BOV part of this thread was not regarding the OEM DV. That things a joke. Mine is replaced with a billet unit.

Also, for record I dont care about noise. Well there is that warbling which has me concerned...

[blackbird82]

well anyone that uses a BOV valve in a diesel is pretty much missing the point.  Intake pressure doesn't matter at all!  after you lift the throttle up fuel supply stops (mostly) but the intake valves are still gonna open.  Next one that does it eats up all the air and so on.. there is no limiting factor in air intake in a diesel throttle up or down.  The real issue is are you properly using all 25psi? pressure alone means almost squat.  Volume means everything.  stock intakes on vw diesels have a nice restriction opening up to four ports.  imagine sucking with 25 psi on a small straw compared to a big one.  too much boost without proper porting can do what happens to me.  blow out intake seals.  

This is from years at John Deere with turbos the size of your engine.

[arb]

As libbybapa says, BOVs are for when the throttle plate shuts and you're still making +20PSI it will blow off pressure to keep the turbo from killing itself or blowing off any of your intake hoses.

I assume everyone here knows that Diesels dont have Throttle plates and therefore they never slap shut, and therefore diesels dont need BOV's.  

The only reason I make this comment is because some Newbie might read this in the future and think that the above comment might mean that "BOV's are needed when the throttle plate shuts".

Obviously I'm stating the obvious.   :roll:    

Sorry to be the barer of bad news guys, but the world is changing. The OEM's are begining to put throttle plates in diesel engines as part of their scheme to reduce emissions.

Has anyone laid hands on the 2009 TDI to know if they have gone to a throttle too ?



http://www.dieselpowermag.com/features/0710dp_2007_dodge_ram_3500_67l_cummins_bluetec/index.html

http://www.whnet.com/4x4/diesel_2.html

http://www3.jetro.go.jp/ttpp/EAN.CR06_EAN?id=1101349&corner_id=999

http://sciencelinks.jp/j-east/article/200521/000020052105A0846836.php

http://www.mitsubishi-fuso.com/en/sales_service/special/2004/download/4M42T_engine.pdf

http://www.freepatentsonline.com/6823660.html

[gigaz2]

all the PD's I've seen have a butterfly valve. NOT used as a throttle.

it opens as soon as you turn the key (before the starter is engaged the valve has to be fully opened) and it closes when shutting off, to suppress the shutdown vibrations and when the ecu detects that the engine is running away.

thats a very good feature BTW

high HP setups swap it out for a free-flowing pipe.

[saurkraut]

Well there is that warbling which has me concerned...

If its warbling that your worried about, a BOV is not the answer.

Compressor stalls are thumps, wumps, or buzzes.

My turbo warbled and made all kinds of weird harmonics when it crapped a blade off the turbine.

Check your turbine wheel for missing or bent turbine blades.

[vanagonturbo]

turbo is rebuilt. warbling happened when it was installed. previous turbo did the same thing. both were T3 units.

previous turbo did not fail, it was just that the rebuilt turbo fell into my lap and I preferred a rebuilt unit over a used one.